Yeah, I don't have a data plan. I look for free WIFI if I need internet.
Not to say that this doesn't work for you, but having a data plan is completely different. Being able to count on the fact that, most of the time, you're able to pull your device out of your pocket and access the internet, whether it's for email, maps, or looking something up is extremely valuable.
It may not be worth the cost for some people, but I will say that before I got my iPhone there were many times where my strategy of "open laptop and see if there's free wifi" failed to work, and occasionally involved driving to the nearest McDonald's trying to pick up their wifi from my car. Not fun.
I was a bit late to the whole smartphone thing, but got my boyfriend's old 3G when he got a new iPhone4. I thought I wouldn't need unlimited data, so I got a plan with cheap data instead. It took two weeks, and then I switched to unlimited data.
Having your phone always on and always connected is a very similar transition as when going from dialup to broadband. No more "I'll look it up on my computer when I get home", instead you can just look it up right now, anywhere.
Agreed, I've owned my first smartphone (an HTC Trophy) for about a year now, the last six months having the data connection on (using prepaid data). It certainly makes the phone a whole different experience.
Sure it's not as convenient to look for wifi, but when I did have a data plan, the actual number of times I'd look something up on the go was so low that it worked out to about $5 per thing looked up. That's just not a cost of convenience I can justify.
Once I cancelled the plan, I soon realized how little I actually NEEDED to look something up on the go. It's a lot like how I got rid of my car and all associated expenses after realizing how little I actually drove it. Now, if I need a car, I'll rent one. That's only happened once so far.
It may not be worth the cost for some people, but I will say that before I got my iPhone there were many times where my strategy of "open laptop and see if there's free wifi" failed to work, and occasionally involved driving to the nearest McDonald's trying to pick up their wifi from my car. Not fun.